Multi-protocol telecommunications routing optimization

ABSTRACT

A telecommunications switching system employing multi-protocol routing optimization which utilizes predetermined and measured parameters in accordance with a set of user priorities in determining the selection of a telecommunications path to be utilized for transmitting a data file to a remote destination. The switching system has a first memory for storing the data file to be transferred, a second memory for storing predetermined parameters such as cost data associated with each of the telecommunications paths, a third memory for storing a set of user priorities regarding the transmission of data files, and means for measuring the value of variable parameters such as file transfer speed associated with each of the telecommunications paths. Processor means are operatively associated with the second and third memories and the variable parameter measuring means for determining which of the plurality of telecommunications paths should be utilized for transferring the data file in accordance with the set of user priorities, the predetermined telecommunications path parameters, and the measured variable parameters. The switching system further comprises input means for allowing a user to change the user priorities in the third memory prior to transmitting a file.

RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.11/948,746, filed Nov. 30, 2007, now U.S. Pat. No. 8,400,926, issuedMar. 19, 2013, which is a continuation of U.S. patent application Ser.No. 10/157,611, filed May 29, 2002, now U.S. Pat. No. 7,307,956, issuedDec. 11, 2007, which is a continuation of U.S. patent application Ser.No. 09/665,399, filed Sep. 20, 2000, now U.S. Pat. No. 6,473,404, issuedOct. 10, 2002, which is a continuation of U.S. patent application Ser.No. 09/198,687, filed Nov. 24, 1998, now U.S. Pat. No. 6,144,641, issuedOct. 20, 2000, which is a continuation of U.S. patent application Ser.No. 08/741,130, filed Oct. 31, 1996, now U.S. Pat. No. 6,016,307, issuedJan. 18, 2000. The subject matter of each of these patent applicationsand/or patents is hereby incorporated by reference herein in theirentireties.

BACKGROUND OF THE INVENTION

This invention relates to telecommunications, and in particular to amethod and apparatus for dynamically selecting an optimaltelecommunications path from a plurality of available paths inaccordance with an analysis of both static and dynamically changingvariables and user priorities.

The telecommunications industry has changed rapidly in recent times fromthe simple analog connection of telephones for voice communications tothe present systems for transmitting and receiving data, facsimile,e-mail, video, audio, as well as voice in both analog and digitalformats (referred to herein collectively as data). Data may betransmitted in any of various formats, such as a data file, datapackets, encapsulated packets, or data streams (referred to herein as adata file). Various types of telecommunications systems have been andcontinue to be installed, which function as the backbone systems fortransmission of data over numerous media. For example, data may betransmitted from one user to another by POTS (plain old telephonesystem), leased lines, mobile cellular networks, digital links, fiberoptics, satellite links, and private and public packet switchingnetworks such as the Internet.

In addition, there exists a great amount of pricing competition amongservice providers employing various types of these transmission media.For example, so-called long distance service providers such as AT&T andMCI offer rates in competition with each other in order to gain greatermarket shares of consumer, business, non-profit organizations, andgovernmental users. As a result of the numerous types of communicationsservices available, as well as the competition between providers ofthese services, users are often faced with difficult choices regardingthe selection of a service which will provide them with the best value.

Often, more than one communications service providers are available at agiven time to a user for selection as a carrier of the data to betransmitted. For example, a user may subscribe to two or more longdistance service providers, and may access either one a given time byfirst dialing the service provider's code, and then dialing thedestination phone number. In addition, a user may have various types ofmedia available for selection; i.e. the connection may be made via theInternet, satellite, etc. This is especially true in a businessenvironment, where economic considerations allow numerous communicationsresources to be available for use.

The prior art generally recognizes low cost as being the factor uponwhich routing decisions are made for the transmission of data. As such,so-called “least cost routing” facilities proliferate, allowing a callto be placed with a service provider that provides the least cost agiven time. PBX (private branch exchange) systems may employ such aleast cost routing facility that automatically connects the callingparty to the destination number along the cheapest route available.

The present invention recognizes that the best value for acommunications medium at a given time is not necessarily the lowest costof the choices available. That is, the optimization of routing selectionencompasses not only a low cost, but also takes into account otherfactors such as transmission bandwidth of the medium, its availabilityat the specific time the user needs to use it, its security, and itsreliability. In addition, a user's priorities may change from time totime, and the requirements regarding the transmission of one data filemay be different than the requirements of another file. That is, a usermay want to transmit one file in an emergency situation at the fastestspeed, regardless of its cost. Other files may need high security frombeing illicitly intercepted, and yet other files may only need to betransmitted at the lowest cost at any time in the near future, with nospeed concerns.

Thus, the present invention recognizes that the selection of the optimalroute for data transmission at a given time is a dynamic analysis thatmust be done in real-time, and must take into account various factorsregarding the available media as well as the priorities of the user andof the file to be transmitted.

U.S. Pat. No. 5,337,352 discloses a PBX system servicing a plurality oftenants, wherein each tenant may specify which of a plurality of routesshould be selected as having the highest priority, then second highestpriority, etc. The routing selections are predetermined by each tenantin accordance with their requirements and available resources, and theselections are stored in a table in the PBX. Once a tenant desires toplace a call, the PBX looks in the table to determine the highestpriority route for that particular tenant, and connects the callaccordingly. If that route is not available, then the next priorityroute, according to the predetermined tenant table, is connected. Thus,a predetermined pecking order is established by each tenant and storedin the PBX. This system is static and not changeable on a real-timebasis since each tenant must predetermine the priority of specificproviders to utilize. Although the system of this patent checks theavailability of the highest predetermined priority route and uses thenext highest priority if it is unavailable, such analysis is only adiscrete yes/no inquiry and does not take into account the currentamount of traffic over the route to analyze the route's availability ona relative basis.

It is therefore an object of the present invention to overcome theshortcomings of the prior art systems as described above.

It is an object of the present invention to provide a system and methodfor selecting an optimal communications path for connecting a call to aremote location for the transfer of a data file thereover by analyzingon a real-time basis a set of multiple protocols.

It is a further object of the present invention to provide such a systemand method for multi-protocol route optimization which analyzes thepriorities of a user regarding the transmission of a particular datafile in determining the optimal route for the call.

It is an even further object of the present invention to provide such asystem and method for multi-protocol route optimization which analyzesvarious factors regarding the route on a real-time basis in determiningthe optimal route for the call.

It is an even further object of the present invention to provide such asystem and method for multi-protocol route optimization which allows auser to override preset default values and specify critical transferparameters on a file-by-file basis.

SUMMARY OF THE INVENTION

In accordance with these and other objects, provided is a communicationsswitching system comprising a first memory for holding a data file to betransferred to a remote destination and a plurality of interfacescoupled with the first memory, wherein each of the interfaces isinterconnected with an associated telecommunications path capable oftransferring the data file to the remote destination. The switchingsystem comprises a second memory for storing predetermined parametersassociated with each of the telecommunications paths and means formeasuring the value of variable parameters associated with each of thetelecommunications paths. A third memory stores a set of user prioritiesregarding the transmission of data files. Processor means is operativelyassociated with the second and third memories and the variable parametermeasuring means for determining which of the plurality oftelecommunications paths should be utilized for transferring the datafile in accordance with the set of user priorities, the predeterminedcommunications path parameters, and the measured variable parameters.The switching system further comprises input means for allowing a userto change the user priorities in the third memory prior to transmittinga file.

For example, the variable parameter measuring means performs ameasurement of the data transfer speed of each of the communicationspaths, for example by a so-called ping test. The predeterminedparameters stored in the second memory comprises the cost per unit timeof utilizing each of the communications paths, which may be a functionof the current time of day and/or current day of week. The predeterminedparameters stored in the second memory also comprises a measure of datatransfer reliability of each of the paths as well as a measure of datatransfer bandwidth of each of the paths. The switching system may alsocomprise means for ascertaining if an interface is available for datafile transfer at a particular time.

In a method aspect utilizing the switching system of the presentinvention, provided is a method of determining which of a plurality ofcommunications paths should be utilized for transferring a data file inaccordance with a set of user priorities, the method comprising thesteps of measuring variable parameters for each of said paths, analyzingthe measured variable parameters and the predetermined parameters inrelation to the user priorities; and determining which of the pathsprovides the characteristics desired by the user for transferring thefile in accordance with the user's priorities.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a functional block diagram of the switching system of thepresent invention utilizing multi-protocol routing optimization;

FIG. 2 is a flowchart of the main routine carried out by the presentinvention; and

FIG. 3 is a flowchart of the interface analysis subroutine carried outby the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

FIG. 1 illustrates a block diagram of the telecommunications switchingsystem 10 of the present invention, which may be implemented for exampleon a personal computer platform, personal digital assistant (PDA),dedicated system such as a PBX, or the like. The switching system 10 isconnected to various communications media in accordance with the user'sresources. In particular, the switching system 10 may be configured to ahigh speed digital link via a T1 interface 12, to a local area network(LAN) via LAN interface 14, to a wide area network (WAN) via a WANinterface 16, to a local loop in a plain old telephone system (POTS) viaPOTS interface 18, and to a wireless communication network via wirelessinterface 20. The interfaces 12, 14, 16, 18 and 20 are exemplary and areprovided for the purposes of illustrating the preferred embodiment ofthe present invention. Thus, in practice, any number of theaforementioned interfaces may be used alone or in any combination asrequired by the user. For example, a number of common carriers such asMCI, AT&T and SPRINT may be configured to the switching system 10 suchthat the user may take advantage of the relative benefits of eachcarrier via the multi-protocol routing optimization to be describedherein. In addition, the wireless interface 20 may be configured forcommunications by any type of wireless communications such as infrared,radio frequency, optical, etc.

Each of the telecommunication media connected to the various interfacesof FIG. 1 has certain parameters associated therewith which areimplemented by the routing methodology of the present invention. Theseparameters are classified by the routing methodology as being eitherpredetermined (fixed) or measurable (variable). Data regarding thepredetermined parameters are stored in a memory 22 in the switchingsystem 10, while data regarding the measurable parameters must becollected by path analysis block 24 from each interface in real-time ator about the time the data file is transferred in order for the routingmethodology to make a proper analysis.

Predetermined parameters stored in memory 32 include, but are notlimited to, the following:

TABLE A $maxbandwidth (i): the maximum amount of bandwidth available forinterface (i). For example, a 28.8 kbs modem would have a $maxbandwidthvariable set to 28.8. $reliability (i): an indication of the reliabilityof interface (i) according to the following scale: 10 = non-reliabletransfer (e.g. wireless) 50 = moderately reliable (e.g. modem) 75 = veryreliable (e.g. T1, WAN) 100 = ultra reliable (e.g. Ethernet LAN)$economy (i): the currency expenditure of interface (i) for a period oftime, normalized so that a high cost interface yields a low measure ofeconomy: $economy (i) = 100 − cost/minute $availability (i) theavailability of interface (i) to a particular user. Not all users of thesystem will have access to each interface; e.g. in a shared PBXenvironment only certain subscribers may have access to the T1interface. $availability = 0 Not available $availability = 1 Available$security (i) an indication of the relative data security of the path,which may example be a function of the number of bits in an encryptionkey (e.g. 1024)

Measurable parameters include, but are not limited to the following:

TABLE B $presentstate (i) the present state of interface (i), indicatingif the telecommunications path is presently operational. $presentstate =0 Not operational $presentstate = 1 Operational $avgstate (i) average of$presentstate (i) over prior five minute window $datasize (i) the sizein KB of the data file to be transmitted. $latency (i) measure in msecof delay through path (i). This is based on a real-time test on theinterface such as by a so-called ping to the remote host. $time time ofday/day of week; this is the same for all interfaces. $availbandwidth(i) available bandwidth of interface (i) at a given time of filetransfer

Rather than simply relying on preprogrammed “least cost” routingcriteria, the present invention utilizes all or a logical subset of thevariables set forth in the Tables A and B above to arrive at a routingdecision for a data file to be transmitted. That is, by employing themulti-protocol routing optimization of the present invention, the pathchosen for transmission of a data file takes into account parameterswhich vary in real-time, thus not relying on a simple preprogrammedlook-up table of low cost providers as in the prior art. In addition,the user can specify his priorities as to the parameters which arecritical in transmitting a particular file, i.e. low cost, high speed,reliability, security, etc., in making the routing determination.

The methodology employed by the present invention is processed byrouting optimization block 26 (which may be implemented in amicroprocessor) and utilizes two main components comprising theparameters set forth in the Tables A and B above in varyingcombinations. The first component is a measure of an inherent efficiencyand desirability of a particular telecommunications path, and is givenby the following equation:$prevalue(i)=$maxbandwidth(i)+$reliability(i)+$economy(i)+$security(i)  (1)

The variable $prevalue is a linear value that increases with a highbandwidth, a high reliability, a high measure of economy (low cost)and/or a high degree of security of a particular path. This variable isessentially unchanging for a given path, except for the fact that the$economy parameter is based in part on the $time variable (cost of thepath is a function of the time of day/day of week) which is derived froma real-time clock 28.

The second component utilized by the routing methodology of the presentinvention is based in part upon real-time parameters that may exhibit awide variance due to numerous reasons, some of which may be beyond thecontrol of the user:$currentvalue(i)=$economy(i)×$speed(i)+$avgstate(i)×10 where$speed(i)=10,000−($datasize(i)×$latency(i)×100)  (2)

so that:$currentvalue(i)=$economy(i)×(10,000−($datasize(i)×$latency(i)×100)+$avgstate(i)×10

Thus, the $currentvalue(i) for a given path (i) will be higher for thepath having a greater economy (low cost), a low data file size, and/orlittle latency through the path (high speed).

The selection of the optimal route to use is then a combination of thevalues calculated above in equations (1) and (2):

$\begin{matrix}{{{\$ finalvalue}(i)} = {{{{\$ prevalue}(i)} + {{\$ currentvalue}(i)}} = {{{\$ maxbandwidth}(i)} + {{\$ reliability}(i)} + {{\$ economy}(i)} + {{\$ security}(i)} + \left( {{{\$ economy}(i)} \times \left( {{10,}{000 - \left( {{{\$ datasize}(i)} \times {{\$ latency}(i)} \times 100} \right) + {{{\$ avgstate}(i)} \times {- 10}}}} \right)} \right.}}} & (3)\end{matrix}$

The routing optimization methodology block 26 then takes the highest$finalvalue(i) for each path in the system that is available,operational, and meets a threshold ($avgstate×10) value of 25 or aboveas shown in the flowcharts to be described below. This methodologythereby allows the optimal selection based on an analysis of multipleprotocols employed by the system, rather than simply a least costrouting decision.

Path analysis function block 24 obtains the value $latency(i) for eachpath(i) by any means known in the art for obtaining the latency of an IPaddressable path, such as by well known software utility known as“ping.” The ping routine sends a packet onto the network and obtains avalue of the average delay encountered by that packet in reaching thedestination and returning. Other techniques which allow the system toobtain a measure of the latency of the path are also encompassed by thepresent invention.

A user may customize the relative weights given to each of the variablesset forth in Tables A, B in accordance with his specific requirements asstored in user priorities memory 32. These fixed weighting values wouldbe stored in a memory in the switching system and used in conjunctionwith the routing methodology for all files transferred in accordancewith the invention. The weighting values are used as multipliers for thevariables in the algorithm in order to allow the user to customize thealgorithm as desired. For example, a user may want to emphasize the$security(i) parameter in the analysis, and may then specify a weightmultiplier of (for example) two so that the $security(i) parameter isweighted twice as much as if the $security(i) parameter were left in thedefault state.

In addition, a user may override via input to a user interface 34 thefixed parameter weights preprogrammed in memory for any given filetransfer with temporary values. The user interface may be any type ofdevice for allowing the user to input data, such as a keyboard, mouse,etc.

In another form of parameter weighting, the user may also force theprogram to ignore certain parameters and focus on one parameter only inarriving at a routing decision. For example, if a user wants to transmita data file 30 to a remote location via the fastest path, regardless ofcost or any other factor, then the user specifies this requirement tothe routing optimization block 26 via the interface 34. The routingoptimization block 26 will then cause all variables except for $latencyto a predetermined factor, so that the path with the smallest value for$latency (i.e. the smallest routing delay) will be chosen by the routingoptimization block 26 as being the fastest route.

Other permutations and variations of the above example can be easilyderived by one skilled in the art to allow the user to specify hispriorities as to data transfer of a file at any given point in time,e.g. the analysis may be forced to look at any two variables, etc.

In addition, a user may store certain sets of parameter weighting to beused in different situations, and then select the set when desired. Theset of weights would then be applied as above described. Furthermore,the program may be configured to automatically apply certain weightingsets as a function of the data type. For example, the user may specifythat all facsimile messages be given a high economy factor, while allvideo files be given a low security factor, etc.

FIGS. 2 and 3 illustrate flowcharts of the methodology employed by thepresent invention in arriving at the optimal choice for routing a datafile amongst a plurality of available paths in accordance with thepresent invention. First, as shown in FIG. 2, the fixed user prioritiesare fetched so that the parameters used in the analysis may be weightedaccordingly. The user is then allowed to enter his temporary priorityoverride values for the file transfer. Assuming for this example that nofixed weighting or temporary override values are entered, then the$finalvalue parameter is determined for each of the paths(i) in theswitching system 10 in the following manner.

First, with reference to FIG. 3, the routing optimization block 26checks with memory 22 to determine if that interface(i) has beenprogrammed as being available to be used by that user be observing thevariable $availability(i). For example, if the switching system 10 isembodied in a PBX system, then not all users will have access to allpaths(i) due to their economic resources. This information is containedin memory 22 and checked as a first step in the process of FIG. 3.

If $availability(i)=0, then $finalvalue(i) is set to zero and theroutine is exited. If, however, the interface(i) is available, the$availabilty(i) is set to 1 and the process proceeds. The routine thenchecks the to see if the path(i) is operable at that time, and the$presentstate variable is returned from the $interface(i) accordingly.If $presentstate(i)=0 (path inoperable or down), then $finalvalue(i) isset to zero and the routine is exited. If $presentstate(i)=1 (pathoperable or up), then the routine proceeds.

The variable $avgstate is then checked to ensure that it is greater thana predetermined threshold value, e.g if $avgstate×10>25. If this istrue, then the interface(i) is considered to be essentially in operablecondition. If false, then the interface(i) is considered to be inessentially non-operable condition, notwithstanding the fact that the$presentstate indicates operability at that particular time.

The routine then proceeds to obtain the $latency(i) value via pathanalysis block 24. Using $latency(i), the variable $speed(i) iscalculated as shown in the flowchart and explained above. The variable$economy(i), which is a function of the $time variable, is obtained fromthe memory 22. Then, the variable $currentvalue(i) is calculated as afunction of $economy(i), $speed(i), and $avgstate(i).

The variable $prevalue(i) is then calculated as a function of thevariables $maxbandwidth(i), $reliability(i), and $security(i), which areobtained from the memory 26, as well as $economy(i) which was previouslydetermined. Finally, the variable $finalvalue is obtained as shown inthe routine, and this is stored in a register pending calculation of$finalvalue(i) for the remaining interfaces as shown in FIG. 2.

After all the interfaces have been analyzed in the above manner, thenthe routing optimization block 26 makes a determination as whichinterface(i) should be selected in accordance with the highest value for$finalvalue(i). The data file is then routed from the memory 30 to theselected interface for transmission.

The routines shown in FIGS. 2 and 3 may be supplemented by the userpriority override features described above, which allow the user tospecify the fastest route, the least cost rout, the most reliable route,etc.

The measurable parameter $availbandwidth(i) may also be utilized in thealgorithms presented herein to provide a real-time indication of thedesirability of selecting a particular interface(i) at a given time.Although the fixed parameter $maxbandwidth(i) provides a measure of themaximum bandwidth that may be available for a given interface, theinterface can be tested if desired in order to determine what portion ofthat bandwidth is actually available for use. One test known in the artfor accomplishing this measurement is the so-called “show interfaceserial zero” test, which may be performed by measuring the amount ofpackets received in the last n seconds as well as how many packets havebeen transmitted on the interface in that time. Thus, the parameter$availbandwidth may be used instead of, or in conjunction with, themeasured parameter $latency to perform the analysis herein.

In addition, while the system and method of the present invention hasbeen shown in conjunction with the transmission of one data file (asdefined herein), it may be also applicable to the transmission ofmultiple data files in either a serial or parallel (interleaved) basis,by modification of the algorithm and routines as may be appropriate.

The choice of particular variables and parameters used herein is thepreferred embodiment; it is anticipated that other variables may be usedin conjunction with the present invention to arrive at the optimal routein a given situation. In addition, the particular algorithm, whiledetermined to provide a requisite relative weighting of the fixed andmeasured variables, may also be supplemented in accordance with therequirements of the user in order to arrive at the optimal routingchoice.

What is claimed is:
 1. In a communications switching system comprising aplurality of interfaces, each of the interfaces interconnected with atleast one of a plurality of communications paths capable of transferringdata to a remote destination, the communications paths including atleast one plain old telephone system (POTS) path, one or more of thecommunications paths having at least one predetermined parameterassociated therewith, a system for determining which of the plurality ofcommunications paths should be utilized for transferring the data, saidsystem for determining comprising at least one processor that:determines a data type of the data to be transferred; measures at leastone variable parameter for at least one of said communications paths;and determines which of the communications paths provides an optimal setof characteristics for transferring the data to the remote destinationin accordance with the at least one measured variable parameter, the atleast one predetermined parameter, and the data type.
 2. The system ofclaim 1, wherein the at least one variable parameter corresponds to anavailable bandwidth on the at least one of said paths.
 3. The system ofclaim 2, further comprising: at least one interface, coupled to the atleast one processor, for transmitting the data to the remote destinationover the path determined to provide the optimal characteristics; whereinthe at least one variable parameter corresponds to the availablebandwidth of the at least one of said paths when the data is transmittedto the remote destination.
 4. The system of claim 1, wherein the atleast one variable parameter corresponds to an operational state of theat least one of said paths.
 5. The system of claim 4, furthercomprising: at least one interface, coupled to the at least oneprocessor, for transmitting the data to the remote destination over thepath determined to provide the optimal characteristics; wherein the atleast one variable parameter corresponds to the operational state of theat least one of said paths when the data is transmitted to the remotedestination.
 6. The system of claim 3, wherein the determining the datatype of the data to be transferred consists of determining whether thedata to be transferred corresponds to a facsimile data type or a furtherdifferent data type.
 7. The system of claim 5, wherein the determiningthe data type of the data to be transferred consists of determiningwhether the data to be transferred corresponds to a facsimile data typeor a further different data type.
 8. The system of claim 3, wherein thedetermining the data type of the data to be transferred consists ofdetermining whether the data to be transferred corresponds to a videodata type or a further different data type.
 9. The system of claim 5,wherein the determining the data type of the data to be transferredconsists of determining whether the data to be transferred correspondsto a video data type or a further different data type.
 10. The system ofclaim 3, wherein the at least one of said paths is a wireless link. 11.The system of claim 5, wherein the at least one of said paths is awireless link.
 12. The system of claim 10, wherein the at least oneprocessor is included in a personal communication device coupled to saidat least one interface, wherein said at least one interface is awireless interface.
 13. The system of claim 11, wherein the at least oneprocessor is included in a personal communication device coupled to saidat least one interface, wherein said at least one interface is awireless interface.
 14. The system of claim 3, wherein the at least oneof said paths is a fiber optic link.
 15. The system of claim 14, whereinthe data to be transferred corresponds to data packets.
 16. The systemof claim 5, wherein the at least one of said paths is a fiber opticlink.
 17. The system of claim 14, wherein the data to be transferredcorresponds to data packets.
 18. The system of claim 1, wherein the atleast one processor determines the path that provides an optimal set ofcharacteristics for transferring the data to the remote destination inaccordance with whether the data comprises an emergency message.
 19. Atelecommunications switching system comprising: a plurality ofinterfaces, each of said interfaces interconnected with an associatedtelecommunications path capable of transferring a data file to a remotedestination; a predetermined parameter associated with each associatedtelecommunications path stored in memory; and a processor capable ofdetermining which associated telecommunications path should be utilizedfor transferring the data file to the remote destination by taking intoaccount the associated predetermined parameter and a variable parameterassociated with the telecommunications path measured by the processor.20. The system of claim 19, wherein the processor is included in apersonal communication device coupled to at least one of said pluralityof interfaces, wherein said at least one of said plurality of interfacesis a wireless interface.